Dual Camshaft Phase Control Assembly

ABSTRACT

The present disclosure employs a pair of camshafts for intake valves. A first phase controller is installed at a first end of the first intake camshaft connecting to a crankshaft. A second phase controller is installed at a second end of the first intake camshaft connecting to a second intake camshaft. Each phase controller can advance or retard phase angles to modify intake valve timing and intake valve lift. This set up is duplicated for the exhaust valves to modulate exhaust valve timing and exhaust valve lift. First and second camshafts are connected via a series of levers, which merge rotational outputs of both camshafts into one. The phase controllers can be differential gear sets, epicyclical gear sets, or a combination thereof.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority to an US Provisional Application #:62/647,166, filed on Mar. 23, 2018, and is a continuation of U.S.Utility application Ser. No. 16/152,720 filed on Oct. 5, 2018, both arehereby incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure, in some embodiments thereof, relates to avariable valve timing mechanism for an internal combustion engine. Morespecifically, it comprises at least one set of phase control assemblyadapted to operate with dual camshafts. The phase control assemblies canindependently and continuously modify both intake and exhaust valvetiming and valve lift, optimized for various running conditions of theengine.

BACKGROUND OF THE INVENTION

There are two common mechanisms to manipulate valves of an internalcombustion engine. One is Variable Valve Timing (VVT), which modifiestiming of opening and closing of intake valves. The other is VariableValve Lift (VVL), which modifies the lift and duration of exhaustvalves. Automakers employs VVT and/or VVL in various models ofautomobiles to optimize engine performance best suited for theirperformance requirements.

One of the challenges automakers faces is cost effectiveness ofmanufacturing such a control mechanism suitable for a wide range ofengine speed. For an engine operating at 3000 revolutions per minute, acamshaft will rotate 25 cycles per second. A VVT thus requires very highprecision in order to offer any performance benefits.

The present disclosure provides a mechanism for an engine to fine tuneits intake timing, intake lift, exhaust timing, and exhaust liftindependently based on its need at various speed level. The aim is tominimize fuel consumption and maximize engine output suitable for itsperformance level. A brief comparison of the present disclosure withprior art is presented in FIG. 19.

BRIEF SUMMARY OF EMBODIMENTS OF THE INVENTION

A pair of camshafts is employed for intake valves. A first differentialgear sets is installed at a first end of the first intake camshaftconnecting to the crankshaft. A second differential gear set isinstalled at a second end of the first intake camshaft connecting to thesecond intake camshaft. Each differential gear set can adjust phaseangle accordingly to modify intake valve timing and intake valve lift.This set up is duplicated for the exhaust valves to modulate exhaustvalve timing and exhaust valve lift.

In a variant, a dual camshaft phase control assembly comprising a firstphase controller connecting a crankshaft and a first end of a firstcamshaft, wherein the first phase controller comprises a first gearsystem to modulate phase relations between the crankshaft and the firstcamshaft. A second phase controller connects a second end of the firstcamshaft and a second end of a second camshaft, wherein the second phasecontroller comprises a second gear system to modulate phase relationsbetween the first and second camshafts. Means to combine rotationaloutput of the first and the second camshafts employs a series of levers.

In another variant, the first gear system of the dual camshaft phasecontrol assembly further comprises a first set of differential bevelgears with a pair of input and output gears to receive and to transmittorque from the crankshaft which in turn drive the first camshaft. Apair of control and spider gears is in meshed relations with the inputand output gears. An actuator, driven by a first control module incommunication with a vehicle's central computing system, can rotate thecontrol gear to modulate phase relations between the crankshaft and thefirst camshaft.

In yet another variant, the input and output gears, the actuator, andthe first control module of the first gear system are arranged in aserial fashion sharing a common rotational axis with the first camshaft.

In a further variant, the first control module drives the output gear ofthe first gear system via a spur gear.

In a variant, the second gear system of the dual camshaft phase controlassembly further comprises a second set of differential bevel gears witha pair of input and output gears to receive and to transmit torque fromthe first camshaft which in turn drive the second camshaft. A pair ofcontrol and spider gears is in meshed relations with the input andoutput gears. An actuator, driven by a second control module incommunication with the vehicle's central computing system, can rotatethe control gear to modulate phase relations between the first andsecond camshafts.

In another variant, the input and output gears, the actuator, and thesecond control module of the second gear system are arranged in a serialfashion sharing a common rotational axis with the second camshaft.

In yet another variant the second control module drives the output gearof the second gear system via a spur gear.

In a variant, the first gear system of the dual camshaft phase controlassembly further comprises a first set of epicyclical gears with a sungear, in gear mesh with a plurality of planet gears, to receive and totransmit torque from the crankshaft, which in turn drives the firstcamshaft. A ring gear encapsulates the planet gears via gear mesh. Aspur gear drives the ring gear to modulate phase relations between thecrankshaft and the first camshaft as instructed by a first controlmodule, which is in communication with a vehicle's central computingsystem.

In anther variant, the sun gear of the first gear system shares a commonrotational axis with the first camshaft.

In yet another variant, the second gear system of the dual camshaftphase control assembly further comprises a second set of epicyclicalgears with a sun gear, surrounded by a plurality of planet gears viagear mesh, to receive and to transmit torque from the first camshaftwhich in turn drive the second camshaft. A ring gear encapsulates theplanet gears via gear mesh. A spur gear drives the ring gear to modulatephase relations between the first and the second camshafts as instructedby a second control module, which is in communication with a vehicle'scentral computing system.

In a further variant, the sun gear of the second gear system shares acommon rotational axis with the second camshaft.

In another variant, the crankshaft and the first camshaft are connectedvia a belt.

In a variant, means to combine rotational output of the first and thesecond camshafts further comprises a plurality of levers each with afirst section configured to be in contact with a first camshaft lobe, asecond section in connection with the first section and configured to bein contact with a second camshaft lobe, and a cam prominent which drivesan engine valve.

In another variant, the means to combine rotational output of the firstand the second camshafts further employs a plurality of levers, arrangedat a pre-determined interval apart from one another, operating inconjunction with the first and the second camshafts lobes to drive aplurality of engine valves via corresponding cam prominents.

In yet another variant, the first and the second camshafts of the dualcamshaft phase control assembly are substantially parallel lengthwise.

Other features and aspects of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, which illustrate, by way of example, the featuresin accordance with embodiments of the invention. The summary is notintended to limit the scope of the invention, which is defined solely bythe claims attached hereto.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of embodiment of the invention, exemplarymethods and/or materials are described below. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and are notintended to be necessarily limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure, in accordance with one or more variousembodiments, is described in detail with reference to the followingfigures. The drawings are provided for purposes of illustration only andto merely depict typical or exemplary embodiments of the invention.These drawings are provided to facilitate the reader's understanding ofthe invention and shall not be considered limiting of the breadth,scope, or applicability of the invention. It should be noted that forclarity and ease of illustration these drawings are not necessarily madeto scale.

Some of the figures included herein illustrate various embodiments ofthe invention from different viewing angles. Although the accompanyingdescriptive text may refer to such views as “top,” “bottom” or “side”views, such references are merely descriptive and do not imply orrequire that the invention be implemented or used in a particularspatial orientation unless explicitly stated otherwise.

FIG. 1 is a schematic drawing of an internal combustion engine with setsof phase control mechanism to continuously modify variable valve timing,as well as variable valve lift for both intake and exhaust valves,according to some embodiments of the present disclosure.

FIG. 2 is a schematic drawing of using 4 differential gear sets as phasecontrol mechanisms, according to some embodiments of the presentdisclosure. This figure also illustrates one of possible installationsamong crankshaft, camshafts, cylinders, phase control gear sets,actuators, and control center.

FIG. 3 is an enlarged view of an area near 32 of FIG. 2, illustrating adifferential gear set connecting Camshaft 41 and 42 on a second end.

FIG. 4 illustrates a top and a side view of Camshaft 41 and 42 withdifferential gear sets installed on both ends

FIG. 5 illustrates a perpendicular sectional view of dual camshafts,profiles of cam lob orientations, a lever, and their relation to thevalve attached.

FIG. 6 illustrates a perpendicular sectional view of dual camshafts in adifferent arrangement with a different type of lever.

FIG. 7 is a diagram illustrating the relation between crank angle (indegrees) and valve lift (in millimeter)

FIG. 8 illustrates cam lobe profiles (controlling valve lift) in degreesof phase shift with crank angles as used in FIG. 7

FIG. 9 is a schematic of a possible installation arrangement among asprocket (driven by crankshaft), a differential gear set for phaseshift, and phase shift control box, according to some embodiments of thepresent disclosure.

FIG. 10 is a schematic of another possible installation arrangement of adifferential gear set and its phase shift control box.

FIG. 11 offers an explosive view of FIG. 10 with main parts disassembledfor illustration purpose

FIG. 12 is a schematic drawing of using 2 epicyclical gear sets as phasecontrol mechanisms, according to some embodiments of the presentdisclosure.

FIG. 13 offers an explosive view of an epicyclical gear set from FIG. 12with main parts disassembled for illustration purpose

FIG. 14 is a schematic of a dual cam system with an epicyclical gear setinstalled on one end, and a differential gear set installed on the otherend.

FIG. 15 illustrates a side view of an epicyclical gear set with itscontrol box. Rotational relations among various parts of the gear set ismarked for demonstrating mechanisms of introducing phase shift

FIG. 16 illustrates an exemplary combined camshaft lobe profiles as itdrives a lever.

FIG. 17 illustrates a perpendicular sectional view of dual camshafts'profiles of a sequence of cam lob orientations when the phase anglebetween first and second camshafts remains at zero.

FIG. 18 illustrates a perpendicular sectional view of dual camshafts'profiles of a sequence of cam lob orientations when the phase anglebetween first and second camshafts is adjusted to a none-zero value.

FIG. 19 is a chart to compare the present disclosure with prior art.

The figures are not intended to be exhaustive or to limit the inventionto the precise form disclosed. It should be understood that theinvention can be practiced with modification and alteration, and thatthe invention be limited only by the claims and the equivalents thereof.

DETAILED DESCRIPTION OF THE OF THE INVENTION

From time-to-time, the present disclosure is described herein in termsof example environments. Description in terms of these environments isprovided to allow the various features and of the invention to beportrayed in the context of an exemplary application. After reading thisdescription, it will become apparent to one of ordinary skill in the arthow the invention can be implemented in different and alternativeenvironments.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of ordinary skillin the art to which this invention belongs. All patents, applications,published applications and other publications referred to herein areincorporated by reference in their entirety. If a definition set forthin this section is contrary to or otherwise inconsistent with adefinition set forth in applications, published applications and otherpublications that are herein incorporated by reference, the definitionset forth in this document prevails over the definition that isincorporated herein by reference.

The present disclosure, in some embodiments thereof, relates to avariable valve timing mechanism for an internal combustion engine. Morespecifically, it comprises at least one set of phase control assemblyadapted to operate with dual camshafts. The phase control assemblies canindependently and continuously modify both intake and exhaust valvetiming and valve lift, optimized for various running conditions of theengine.

Referring to FIGS. 1˜4, the present disclosure employs two camshafts, 41& 42 (FIG. 2), arranged in parallel to each other to control intakevalves. A separate pair of camshafts, 43 & 44, in similar configurationsis designated to control exhaust valves. A phase control assembly refersto a pair of gear sets installed on both ends of a pair of camshafts.For instance, in FIG. 1, an epicyclical gear set 91 and a differentialgear set 22 are installed on both ends of a pair of camshafts 41 and 42to control intake valves, and to modify their phase relations accordingto engine needs. Another pair of phase control assembly, comprising gearsets 93 and 24, modifies phase relations of camshafts 43 and 44, whichcontrol exhaust valves.

FIG. 2 illustrates another exemplary embodiment with engine casingremoved for a better view of the assemblies. Differential gear sets 21and 22 are installed on both ends of camshafts 41 and 42, which controlsintake valves. Another set of differential gears 23 and 24 are installedon both ends of camshafts 43 and 44, which controls exhaust valves.

Camshafts 41 and 43 can be driven directly by crankshaft 51 via a chainor a belt in meshed relations with gears connecting gear sets 21 and 23.Camshafts 42 and 44 can be driven indirectly by crankshaft 51 via ringgears, in meshed relations with camshafts 41 and 43, and also connectinggear sets 22 and 24.

Camshafts Sensor 01 measures crankshaft angle. Sensors 02 and 03 measureintake camshafts' angle (41 and 42) respectively. Sensors 04 and 05measure exhaust camshaft's angle respectively (43 and 44). All sensormeasurements are taken in real time, and their output signals areconstantly transmitted to an automobile's main computer.

Each differential gear set comprises a control shaft installed coaxiallyat the end of a camshaft, and can be independently adjusted via anactuator to change its phase (or angular) relations with the camshaft.Actuator 31 rotates control shaft 11 of differential gear set 21 toadvance or to retard phase relations between crankshaft and first intakecamshaft 41. Actuator 32 rotates control shaft 12 of differential gearset 22 to advance or to retard phase relations between first intakecamshaft 41 and second intake camshaft 42. Actuator 33 rotates controlshaft 13 of differential gear set 23 to advance or to retard phaserelations between crankshaft and first exhaust camshaft 43. Actuator 34rotates control shaft 14 of differential gear set 24 to advance or toretard phase relations between first exhaust camshaft 43 and secondexhaust camshaft 44.

FIG. 3 illustrates an enlarged perspective view of differential phasecontrol gear set 22, which connects intake camshafts 41 and 42, as inone of possible embodiments of the present disclosure. The maincomponents of this differential gear sets are: first bevel gear 64,second bevel gear 65, spider gear 66, control gear 67, and ring gear 62attached to a housing 63. Rotation propagating from first intakecamshaft 41 drives end gear 61, which in turn drives ring gear 62, whichfurther in turn drives second intake camshaft 42. Since housing 63 iswelded onto ring gear 62, they both rotate around axis 120. Withinhousing 63, first and second bevel gears 64 and 65 are in gearmesh withspider gear 66 and control gear 67. First and second bevel gears 64 and65 thus rotate around their axis 110, which allow the housing to rotateround axis 120 while in gearmesh with spider gear 66 and control gear 67at the same time.

Note that gears 66, 67, 64, and 65 do not need to be identical, so longas the differential and phase change functionalities are preserved.Parameters, such as sizes and scale, are not drawn in proportion, andcan take different values based on an engine's particular needs. Figuresare for exemplary illustration purpose only. Variations are acceptablefor different gear mesh angle, ratio, whether to use straight bevelteeth or spiral bevel teeth etc.

When phase shift is needed either in the advance or in the retarddirection between first and second intake camshafts 41 and 42, actuator32 rotates control shaft 12, which rotates control gear 67 around axis120 several degrees forward or backward. This additional rotation,whether forward (in addition) or backward (in subtraction), propagatesthrough meshed gears 64, 65, 66, housing 63, and ring gear 62, whichdrives second intake camshaft 42. The actual amount of phase shift andphase shift timing is controlled by the automobile's main computersystem, taken into account various parameters such as engine speed,load, camshaft sensors (02 and 03) readings etc.

A top and a side view of the dual camshafts with phase control assemblyinstalled are illustrated in FIG. 4, according to one of the embodimentsof the present disclosure. In the top view, a phase control differentialgear set 21, aimed to modify phase relations between crankshaft andfirst intake camshaft, further comprises a spur gear 321 in mesh withring gear 322. A local control module 331, such as an electric motor,drives the actuator 31 to change phase accordingly. A local controlmodule 332 can also be installed in a serial fashion to directly driveactuator 32 without additional spur gears. This exemplary arrangementillustrates that actuators 31 and 32 can be modified to drive differentgears of a gear set, so long as the phase change capabilities arecomparable. Dimensions and constrains of an engine compartment may verywell determine the physical location of a control module and how it isconnected to drive the gear sets to modify phase relations.

FIGS. 5 and 6 illustrates perpendicular sectional views of dualcamshafts 41 and 42, and the connections thereof, according to someembodiments of the present disclosure. Axis 511 is defined by connectingthe center of camshaft 41 and the tip of its camshaft lobe. Axis 513 isdefined by connecting the center of camshaft 42 and the tip of itscamshaft lobe respectively. Reference line 512 is drawn to be parallelto Axis 511, thus defines a phase angle 501 between first intakecamshaft 41 and second intake camshaft 42. This phase angle can beactively adjusted in either direction by rotating control shaft 12 tomodify control gear 67 via differential gear set 22 (FIGS. 2 and 3)installed at a second end of the first and second intake camshafts 41and 42.

As both camshafts lobes rotate, it pushes against lever 553, andtranslate the motion through cam prominent 554 to push onto spring 551,which in turn, lead to the opening and closing of valve 552. FIG. 6illustrates a different exemplary type of lever 653, where first intakecamshaft 641 and second intake camshaft 642 are arranged near ends oflever 653 on opposing sides. Phase angle 601 is defined by axis 613 andreference line 612, which is parallel to axis 611. Rotations of bothcamshaft lobes push against lever 653, and translate the motion throughcam prominent 654 and spring 651 to open and to close valve 652. Leverssuch as 553 and 653 can be manufactured into different shapes withdifferent profiles, so long as their functionalities are preserved,which is to combine and merge the rotational output of both first andsecond camshafts.

First camshaft and second camshaft are connected via a series of levers553 (FIG. 11), which merges the rotations of both camshafts into one.When camshaft lobes, from both camshafts, are set at an angle (phaseangle), the envelope of the combined rotational path drives the leversaccordingly. An exemplary camshafts lobes profile combination isillustrated in FIG. 16 as they drive the lever together. The phase anglebetween the two camshafts are set at 40 degrees, as the combinedcamshaft lobes rotate from 35 to 70 degrees with respect to a commonreference line, it pushes the lever 26.17 mm and 35.85 mm downwardsrespectively.

FIGS. 17-18 illustrate several perpendicular sectional views of dualcamshafts, profiles of sequences of cam lob orientations when the phaseangles between first and second camshafts are set at various zero ornone-zero values. In FIG. 17, phase angle between the first and thesecond camshafts are set at zero degree. First camshaft is drivendirectly by the crankshaft. An example can be shown in FIG. 3, whererotation of first camshaft 41 (driven by crankshaft) propagates viagears 61, 62, and further onto second camshaft 42. Parameters, such assizes and scale, are not drawn in proportion, and can take differentvalues based on an engine's particular needs.

As the crankshaft drives the first camshaft +20 or −20 degrees in FIG.17, the phase relations between the first and second camshafts remainconstant (set at zero). Therefore, an axis passing through the center ofthe first camshaft and the tip of its cam lobe is parallel to an axispassing through the center of the second camshaft and the tip of itscorresponding cam lobe. A mathematical representation of a fullrotational cycle is illustrated immediately below, and corresponds tothe physical example of the camshafts set at 0, +20, and −20 degrees.

FIG. 18 illustrates two examples where the first and second camshaftsare set at 20 and 40 degrees. In other words, an axis passing throughthe center of the first camshaft and the tip of its cam lobe is at a 20and a 40 degrees angle with an axis passing through the center of thesecond camshaft and the tip of its corresponding cam lobe. This isachieved by adjusting actuator 32 as illustrated in FIG. 3 and describedin the previous section. A mathematical representation of a fullrotational cycle is illustrated immediately below, and corresponds tothe physical example of the camshafts set at 0, 20 and 40 degrees. Thecondition where the angle is set at 0 is carried over from FIG. 17 forreference purpose. If the angles between the first and second camshaftswere set at −20 and −40 degrees, the curves will be mirror images ofthose illustrated in FIG. 18, with respect to the 0 degree curve.

In FIG. 2, differential gear set 21 is installed between the crankshaftand the first intake camshaft 41 at a first end. A phase change based onthe adjustment of control shaft 11 modifies the timing of opening andclosing of the intake valve. Differential gear set 22 is installedbetween the first intake camshaft 41 and the second intake camshaft 42at an opposing end. A phase change adjustment of control shaft 12modifies the duration of opening of the intake valve, i.e. how long orshort the intake valve stays open. These two gear sets can be adjustedindependently of each other. The present disclosure thus provides amechanism to separately modify intake valve timing and intake valve liftduration.

In an example illustrated in FIG. 7, crankshaft completes two fullrotation cycles, and both first and second intake camshafts complete onefull rotation cycle. Crankshaft and first intake camshaft maintain aconstant phase relations, while phase angle is modified only betweenfirst and second intake camshafts. In other words, intake valve timingremains constant, while intake valve lift duration changes. X-axisrepresents crank angle (maintained constant with respect to first intakecamshaft), and Y-axis represents valve lift (in mm). Different symbolsrepresent degrees of phase shift induced by adjusting control shaft 12of gear set 22 (FIG. 2). FIG. 8 illustrates corresponding camshaft lobeprofiles in terms of phase shift. FIG. 7 demonstrates that higherdegrees of phase shift between first and second intake camshaftscorrespond to longer intake valve duration, i.e., the intake valve staysat maximum lift (fully opened position in mm) longer. FIG. 7 illustratesphase shifts in one direction only. The whole curve will shift to theright, if the phase shifts were desired in the opposition direction. Itshould be noted that parameters used in the graph are examples fordemonstrative purpose only. Different engines or different performancelevels can choose different parameter ranges accordingly.

FIGS. 9-11 illustrate several alternative embodiments of the presentdisclosure. The phase control assembly comprises at least two phasecontrol gear sets installed on both ends of a pair of camshafts thatcontrols valve timing and its lift duration. Previous embodiments haveused intake valves as examples. It should be noted that the same is truefor exhaust valves as well.

FIG. 9 and FIG. 10 illustrates a close up of FIG. 2 with four camshafts41, 42, 43 (under engine cover), and 44. Camshafts 41 and 42 aredesignated to modify intake valve timing and intake valve lift duration.Camshafts 43 and 44 are designated to modify exhaust valve timing andexhaust valve lift duration. In FIG. 9, local control modules 931 and933 are installed on sides of the engine, and are in gear mesh relationswith spur gears 941 and 943, which in turn change phase angle betweenthe crankshaft and camshafts 41 and 43 to modulate first intake andfirst exhaust valve timing. Alternatively, the crankshaft can directlydrive both differential gear sets via a belt or chain, as in FIG. 2. InFIG. 10, local control modules 951, 952, 953 and 954 are installed in aserial manner and each drives its corresponding actuators directly tomodify phase angels. FIG. 11 illustrates an exemplary explosive view ofvarious parts of the camshaft control module assembly with axis ofrotations arranged in one of many possible embodiments.

FIGS. 12-15 illustrate an alternative embodiment where an epicyclicalgear set, instead of a differential gear set, is employed to achievephase control. Epicyclical gear set 91 and 93 are installed between thecrankshaft and the first intake camshaft 41 and first exhaust camshaft43. Gear 991 and 993 are in mesh relations with the crankshaft with achain or a belt. An exemplary epicyclical gear set, as illustrated inFIG. 13, comprises a sun gear 971 in the center, surrounded by aplurality of planet gears 961 via gear mesh, and a ring gear 962 furtherencloses all the planet gears via gear mesh. Rotation of the sun gear971 is directly driven by the crankshaft and propagates to the firstintake camshaft 41. When no phase shift is needed, crankshaft angleremains in a constant relation with the camshaft. Phase shift isintroduced by rotating the ring gear 962 in either direction, which inturns rotates the planet gears 961 via gear mesh (around their ownaxis), and thus further drive the sun gear and camshaft 41. A localcontrol module, in some exemplary embodiment, employs a spur gear 941 tointroduce phase shift (in either advance or in retard direction) bydriving the ring gear 962 via gear mesh. A side view of the epicyclicalgear set in FIG. 15 illustrates the rotational relations among the sun,the planet, and the ring gears.

It should be noted that the effects of phase shift, whether introducedvia a differential gear set or via an epicyclical gear set iseffectively equivalent. FIG. 14 illustrates an exemplary arrangementwhere an epicyclical gear set 91 is installed at a first end of anintake camshaft 41, and a differential gear set 22 is installed at asecond end of the intake camshafts 41 and second camshaft 42. Dependingon feasibility or configuration of an engine compartment, anycombination thereof should achieve comparable results as described inthe present disclosure. Differential gear set and/or epicyclical gearset are well documented in prior art. Numerous variations of the gearset itself are acceptable so long as its functionalities are preservedfor the purpose of the present disclosure.

While various embodiments of the present disclosure have been describedabove, it should be understood that they have been presented by way ofexample only, and not of limitation. Likewise, the various diagrams maydepict an example architectural or other configuration for theinvention, which is done to aid in understanding the features andfunctionality that can be included in the invention. The invention isnot restricted to the illustrated example architectures orconfigurations, but the desired features can be implemented using avariety of alternative architectures and configurations. Indeed, it willbe apparent to one of skill in the art how alternative functional,logical or physical partitioning and configurations can be implementedto achieve the desired features of the present disclosure. Also, amultitude of different constituent module names other than thosedepicted herein can be applied to the various partitions.

Although the invention is described above in terms of various exemplaryembodiments and implementations, it should be understood that thevarious features, aspects and functionality described in one or more ofthe individual embodiments are not limited in their applicability to theparticular embodiments with which they are described, but instead can beapplied, alone or in various combinations, to one or more of the otherembodiments of the invention, whether or not such embodiments aredescribed and whether or not such features are presented as being a partof a described embodiment. Thus the breadth and scope of the presentdisclosure should not be limited by any of the above-described exemplaryembodiments.

Terms and phrases used in this document, and variations thereof, unlessotherwise expressly stated, should be construed as open ended as opposedto limiting. As examples of the foregoing: the term “including” shouldbe read as meaning “including, without limitation” or the like; the term“example” is used to provide exemplary instances of the item indiscussion, not an exhaustive or limiting list thereof; the terms “a” or“an” should be read as meaning “at least one,” “one or more” or thelike; and adjectives such as “conventional,” “traditional,” “normal,”“standard,” “known” and terms of similar meaning should not be construedas limiting the item described to a given time period or to an itemavailable as of a given time, but instead should be read to encompassconventional, traditional, normal, or standard technologies that may beavailable or known now or at any time in the future. Likewise, wherethis document refers to technologies that would be apparent or known toone of ordinary skill in the art, such technologies encompass thoseapparent or known to the skilled artisan now or at any time in thefuture.

A group of items linked with the conjunction “and” should not be read asrequiring that each and every one of those items be present in thegrouping, but rather should be read as “and/or” unless expressly statedotherwise. Similarly, a group of items linked with the conjunction “or”should not be read as requiring mutual exclusivity among that group, butrather should also be read as “and/or” unless expressly statedotherwise. Furthermore, although items, elements or components of theinvention may be described or claimed in the singular, the plural iscontemplated to be within the scope thereof unless limitation to thesingular is explicitly stated.

The presence of broadening words and phrases such as “one or more,” “atleast,” “but not limited to” or other like phrases in some instancesshall not be read to mean that the narrower case is intended or requiredin instances where such broadening phrases may be absent.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable sub-combination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

What is claimed is:
 1. A dual camshaft phase control assemblycomprising: a crankshaft; a first camshaft; a second camshaft extendingparallel to the first camshaft; a first phase controller coupled to thecrankshaft and a first end of the first camshaft, the first phasecontroller further comprises a first differential gear system comprisinga first pair of input/output gears, a first spider gear, and a firstcontrol gear driven via a first actuator configured to advance or toretard a phase relation of the first camshaft with respect to thecrankshaft; a second phase controller coupled to a second end of thefirst camshaft and a second end of a second camshaft, the second phasecontroller further comprises a second differential gear systemcomprising a second pair of input/output gears, a second spider gear,and a second control gear driven via a second actuator configured toadvance or to retard a phase relation of the second camshaft withrespect to the first camshaft; and means to combine rotational output offirst camshaft lobes and second camshaft lobes respectively coupled tothe first and second camshafts.
 2. The dual camshaft phase controlassembly of claim 1, wherein the first pair of input/output gearscomprise bevel gears configured to transmit torque from the crankshaftto the first camshaft, the spider gear and the first control gearcomprise bevel gears configured to mesh with the first pair ofinput/output gears; and the first actuator is driven by a first controlmodule in communication with an electronic control unit.
 3. The dualcamshaft phase control assembly of claim 2, wherein the first inputgears, the first differential gear system, the first actuator, and thefirst control module are arranged in series along a common rotationalaxis with the first camshaft.
 4. The dual camshaft phase controlassembly of claim 2, wherein the first control module drives the outputgear of the first differential gear system via a first spur gear.
 5. Thedual camshaft phase control assembly of claim 1, wherein the second pairof input/output gears comprise bevel gears configured to transmit torquefrom the first camshaft to the second camshaft, the spider gear and thesecond control gear comprise bevel gears configured to mesh with thesecond pair of input/output gears; and the second actuator is driven bya second control module in communication with an electronic controlunit.
 6. The dual camshaft phase control assembly of claim 5, whereinthe second input gears, the second differential gear system, the secondactuator, and the second control module are arranged in series along acommon rotational axis with the second camshaft.
 7. The dual camshaftphase control assembly of claim 5, wherein the second control moduledrives the output gear of the second differential gear system via asecond spur gear.
 8. A dual camshaft phase control assembly comprising:a crankshaft; a first camshaft; a second camshaft extending parallel tothe first camshaft; a first phase controller coupled to the crankshaftand a first end of the first camshaft, the first phase controllerfurther comprises a first epicyclical gear system comprising a first sungear meshing with a first plurality of planet gears so as to transmittorque from the crankshaft to the first camshaft, a first ring gearconfigured to encapsulate and mesh with the first plurality of planetgears, and a first spur gear configured to drive the first ring gear soas to advance or to retard a phase relation of the first camshaft withrespect to the crankshaft; a second phase controller coupled to a secondend of the first camshaft and a second end of a second camshaft, thesecond phase controller further comprises a second epicyclical gearsystem comprising a second sun gear meshing with a second plurality ofplanet gears so as to transmit torque from the first camshaft to thesecond camshaft, a second ring gear configured to encapsulate and meshwith the second plurality of planet gears, and a second spur gearconfigured to drive the second ring gear so as to advance or to retard aphase relation of the second camshaft with respect to the firstcamshaft; and means to combine rotational output of first camshaft lobesand second camshaft lobes respectively coupled to the first and secondcamshafts.
 9. The dual camshaft phase control assembly of claim 8,wherein the first spur gear is driven by a first control module incommunication with an electronic control unit.
 10. The dual camshaftphase control assembly of claim 8, wherein the first sun gear shares acommon rotational axis with the first camshaft.
 11. The dual camshaftphase control assembly of claim 8, wherein the second spur gear isdriven by a second control module in communication with an electroniccontrol unit.
 12. The dual camshaft phase control assembly of claim 8,wherein the second sun gear shares a common rotational axis with thesecond camshaft.
 13. The dual camshaft phase control assembly of claim1, wherein the crankshaft and the first camshaft are coupled via a belt.14. The dual camshaft phase control assembly of claim 1, wherein themeans to combine rotational output of the first and the second camshaftlobes comprises: a plurality of levers each with a correspondingcamshaft lobe of the first camshaft lobes and a corresponding camshaftlobe of the second camshaft lobes, respectively; and a lever protrusionconfigured to drive an engine valve.
 15. The dual camshaft phase controlassembly of claim 1, further comprising a plurality of levers, arrangedat a pre-determined interval apart from one another, operating inconjunction with the first and the second camshafts lobes so as to drivea plurality of engine valves via corresponding lever protrusions.
 16. Amethod to modulate phase relations of dual camshafts comprising:coupling a first phase controller to a crankshaft and a first end of thefirst camshaft, the first phase controller further comprises anepicyclical gear system comprising a first sun gear meshing with a firstplurality of planet gears so as to transmit torque from the crankshaftto the first camshaft, a first ring gear configured to encapsulate andmesh with the first plurality of planet gears, and advancing orretarding a phase relation of the first camshaft with respect to thecrankshaft by driving a first spur gear meshed with the first ring gear;coupling a second phase controller to a second end of the first camshaftand a second end of a second camshaft, the second phase controllerfurther comprises a differential gear system comprising a pair ofinput/output gears, a spider gear, and a control gear; and advancing orretarding a phase relation of the second camshaft with respect to thefirst camshaft by driving an actuator meshed with the control gear; andcombining rotational output of first camshaft lobes and second camshaftlobes respectively coupled to the first and second camshafts.
 17. Themethod to modulate phase relations of dual camshafts of claim 16,wherein the first spur gear driving the first ring gear receivesinstructions from a first control module in communication with anelectronic control unit.
 18. The method to modulate phase relations ofdual camshafts of claim 16, wherein the first sun gear shares a commonrotational axis with the first camshaft.
 19. The method to modulatephase relations of dual camshafts of claim 16, wherein the pair ofinput/output gears, the actuator, and the control gear of thedifferential gear system are arranged in a serial fashion sharing acommon rotational axis with the second camshaft.
 20. The method tomodulate phase relations of dual camshafts of claim 16, wherein theoutput gear of the differential gear system is driven by a second spurgear in communication with an electronic control unit.